Heat exchangers which employ two spaced header and tank constructions and wherein generally paralleled, open ended tubes interconnect the header and tank constructions and are in fluid communication with the interior of the header and tank constructions are known. Plate or serpentine fins can be disposed across the tubes between the header and tank constructions. These heat exchangers can be used in vehicular radiators and air conditioner condensers, evaporators and the like.
Structural improvements in such heat exchangers are desired to enhance the ease of manufacture and reduce the cost of manufacture and manpower while maintaining or improving durability and reliability. A round tube (1 pc) is always lighter. Lighter and more effective heat exchangers especially for vehicular radiators and air conditioners are sought after advantages.